Fulvic acid removal by nanoparticle TiO2 using a submerged membrane photocatalysis reactor

The degradation of fulvic acid(FA) by nanoparticle TiO_2 in a submerged membrane photocatalysis(SMPC) reactor was studied. In this reactor, photocatalytic oxidation and membrane separation co-occured. The continuous air supplier provided O_2 for the photocatalytical reaction and mixed the solution through an airflow controller. The particle TiO_2 could automatically settle due to gravity without particle agglomeration so it could be easily separated by microfiltration(MF) membrane. It was efficient to maintain high flux of membranes. The effects of operational parameters on the photocatalytic oxidation rate of FA were investigated. Results indicated that photocatalyst at 0.5 g/L and airflow at 0.06 m~3/h were the optimum condition for the removal of fulvic acid, the removal efficiency was higher in acid media than that in alkaline media. The effects of different filtration duration on permeate flux rate of MF with P25 powder and with nanoparticle TiO_2 were compared. Experimental results indicated that the permeate flux rate of MF was improved and the membrane fouling phenomenon was reduced with the addition of nanoparticle TiO_2 catalyst compared with conventional P25 powder. Therefore, this submerged membrane photocatalysis reactor can faciliate potential application of photocatalytic oxidation process in drinking water treatment.